When a jet-powered aircraft lands, the landing gear brakes and aerodynamic drag (e.g., flaps, spoilers, etc.) of the aircraft may not, in certain situations, be sufficient to slow the aircraft down in the required amount of runway distance. Thus, jet engines on most aircraft include thrust reversers to enhance the braking of the aircraft. When deployed, a thrust reverser redirects the rearward thrust of the jet engine to a generally or partially forward direction to decelerate the aircraft. Because at least some of the jet thrust is directed forward, the jet thrust also slows down the aircraft upon landing.
Various thrust reverser system designs are commonly known, and the particular design utilized depends, at least in part, on the engine manufacturer, the engine configuration, and the propulsion technology being used. Regardless of the specific thrust reverse system used, each includes thrust reverser movable components that are selectively deployed to enhance the braking of the aircraft, and thereby shorten the stopping distance during landing and reduce the burden on landing gear brakes. During the landing process, the thrust reverser movable components may be deployed to assist in slowing the aircraft. Thereafter, when the thrust reversers are no longer needed, the thrust reverser movable components are returned to their original, or stowed, position.
The thrust reverser movable components are moved between the stowed and deployed positions by actuators. Power to drive the actuators may come from one or more drive units, which may be electric, pneumatic, or hydraulic drive, depending on the system design. A drive train that includes one or more drive shafts, such as flexible rotating shafts, may interconnect the actuators and the one or more drive mechanisms to transmit the drive mechanism drive force to the thrust reverser movable components and/or to synchronize the reverser components.
Hydraulically-driven thrust reverser systems have been historically used in aircraft because of the robustness of hydraulic components and the abundant availability of hydraulic fluid onboard most aircraft. Unfortunately, these systems also suffer drawbacks. For example, these systems may leak, which can cause environmental and other (e.g., fire zone) concerns. These systems may require significant flow and/or require hydraulic fluid to be present in the actuators or other components, which can increase weight.
Hence, there is a need for an aircraft thrust reverser actuation system that includes the robust features of a hydraulically-driven system, but does not suffer the environmental and weight issues associated with presently known systems. The present invention addresses at least these needs.